Hardest hit will be Africa & the Middle East. They rely on imports. For what they do grow they will be restricted on fertilizer unless they are on Russia's approved list. Prices will rise in North America but we won't see shortages across the board. Between Canada, Mexico, and USA we are flush with food and fertilizer. It's everyone who relies on Russia/Ukraine that's fucked. In the end I really doubt Russia won't begin exporting fertilizer again. The price is so high now they'd be nuts not to reap the windfall from that.